"The History of the Greek Rite Catholics in Pannonia, Hungary, Czechoslovakia and Podkarpatska Rus' 863-1949" by John Slivka. Details religious and political history of the Rusin (Rusyns) or Ruthenian Catholics (Eastern Rite Catholic in union with the Pope of Rome). The Ruthenian Eastern Rite Catholics established communion with the Pope and separated from Eastern Orthodoxy but retained many of the traditions of the Orthodox Church. Despite being in union with the Latin Church, there remained many tensions between the Latin Rite and Eastern Rite Catholics as well as tensions with Orthodoxy.